When Yale University student Molly Clark-Barol got the invitation, she was reluctant to go. A naked party? Where people stand around without any clothes on? It sounded way too awkward.
But she decided to check it out and says she found the experience "kind of liberating."
"It was really low key, kind of just like any other party," says Clark-Barol. "Except you're naked."
Yale is one of several Ivy League schools at which naked parties are part of the campus culture. Ask the partygoers why they attend and they may tell you something about releasing academic pressure, self-expression or experimentation.
But push them a bit more and you'll find that when you put 30 or so naked college kids together in a room, the pulse of youthful rebellion runs strong.
Most parties at Yale begin with a cryptic invitation, like this one recently sent to a Yale student:
"You are invited to a Party this Hallow's Eve. Meet on Cross Campus…at 11, 11:30, Midnight…The location will be revealed, as will you."
Held late in the evening, the parties are usually a last stop after an evening of social revelry. Full of liquid courage, the naked partygoers check their coats -- and their clothes -- at the door. The guest lists for the smaller parties are usually limited to around 30 or 40 people, and the conversations tend to be more intellectual, partygoers claim.
And there are strict rules about touching and gawking. If guests start getting too friendly with each other, they're asked to leave.
"It's more about breaking taboos," says Clark-Barol. "You feel more like running around in circles than hooking up with someone."
The tradition of naked parties at Yale is not new. In the 1990s, a naked party held in a small campus dining area called the Buttery was dubbed, "Nude Night at the Butt." Also in the late 1990s, a secret society called "Porn 'n Chicken," met together to watch pornographic movies while eating fried chicken in the nude, sources tell ABCNEWS.com.
The club gained national attention after its leaders threatened to make their own pornographic movie starring Yale students. Though the film was never released, in 2002, Comedy Central produced a fictionalized TV movie depicting the club's activities.
The prevalence of naked parties on college campuses is not only a Yale phenomenon -- the university shares a certain national notoriety for the tradition with its fellow Ivy, Brown University, according to Luke Skurman, CEO of College Prowler, Inc., a company that produces "insider" guides written by students for over 230 colleges.
A student society on the Yale campus called "The Pundits" is famous for the several naked parties it hosts each year, but it members like to keep their identities anonymous. They don't want the Yale administration to know who they are.
But the Yale administration seems to stay away from the parties, as long as they are "safe."
"Yale trusts its students, we give them a lot of latitude and independence," says Gila Reinstein, a spokesperson for the university. "We don't intervene with their social lives or their extracurricular activities."
Experts say that like the streakers of the 1970s, naked partyers at college are after self-expression and stress relief.
"In college you see a lot of experimentation," said Dr. Sandra L. Coren, author of "Sex Matters for College Students: Sex FAQs in Human Sexuality." "They're making a statement about being free."